Added polish guide
fix incorrect file status.
Update rest-rate-limiting.md

Чуть улучшил ясность написанного.
Update rest-rate-limiting.md
updated guide about i18n and ICU

fixes #2593
Fixes #3197: Using `ActiveQuery::indexBy()` may cause relational AR queries to generate incorrect relational results
chanded jui DatePicker widget to use ICU date format

- use default application formatting for the date value
- auto adjust to application language and format setting changes
- be consistent with formatter and date validator

fixes #1551
Update .travis.yml

caching cubrid breaks the build on a regular basis and has nearly no speedup
Fixes #5106: Refactored query caching to not load cache component when query caching is not used at all.
[NL] Updated translations
Merge pull request #5154 from bedezign/master

[skip ci] [NL] Updated translations
Merge pull request #5148 from githubjeka/patch-1

[ci skip] Updated RUS TRANSLATION rest-rate-limiting.md
added missing documentation about the NOT operator in Query

fixes #5147
ignore invalid date format and just display value as is

fixes #5155
reverted addition of $where property
doc typo

fixes #5147
[ci skip]
Fixes #5147: null is not handled correctly for arbitrary operator in SQL.
fixes for sphinx.
added docs for #5147
Update finnish translation